I was in a similar situation a few years ago. And it really is bloody awful. The eldest son of the family that were next to us had a few mental issues and would contantly argue (i.e. shoutdown) his parents and siblings, who were also noisy as hell.
I'm talking loud as hell music from the boy and his family playing all night, every night, while the guy lent out the window to scream threats at my mother and brother.
In the end we got a thing called a Noise Abatement charge put on them, which meant if we complained about the noise again, the police would come and seize everything that could be used to make noise in their home. Everything. Stereos, computers, tv's the lot.
So they did it again, and we called. And the took to opening all the car doors and leaving the music blaring from the cars at all hours of the night out of spite.
The sad thng is, at the end of the day all we could do was wait for them to leave. Which they did, eventually. But it was still several years of hell.
Sorry you're having to deal with your situation, but I think you're only option is formal complaints. Even though we're all well aware of how useless some local councils are.